1. Field of the Invention
The present invention relates to nanostructure formation tools and, more particularly, to a nanoimprinting apparatus.
2. Description of Related Developments
Consumers continue to express a desire for ever more sophisticated electrical and electronic devices. However, though consumers expect the devices to have more memory, more features, faster processing and an even smaller size than earlier devices, they are unwilling to accept price increases for the devices. This has fueled a demand for mass-production of integrated circuits (IC) with smaller circuit features. For example, there is currently a demand for IC""s with sub-50NM structures. Nevertheless, conventional lithography processes have proven to be unable to produce sub-50NM structures in a cost effective manner. For example, electron beam lithography has been used to generate structures in the scale of 10NM, but electron beam lithography is costly. Nanoimprinting techniques have been demonstrated to efficiently produce patterns with sub-25NM features. One example of a conventional nanoimprinting process is disclosed in U.S. Pat. No. 5,772,905, issued Jun. 30, 1998. Generally, this process involves having a mold with a pattern therein, that is pressed into a thin film carried on substrate. As can be realized, the pattern on the mold is thus used to mold a complementing pattern on the substrate, and hence the mold pattern itself has substantially the xe2x80x9coppositexe2x80x9d profile than the desired pattern formed on the substrate. The nanoimprinting process has also proven successful in fabrication of micro electro-mechanical systems (MEMS). These devices have potential for use in numerous applications such as biomedical, biofluidics, microoptics, and nanotechnology applications.
Generally, nanoimprinting involves one of two processes; micro-contact printing, and hot embossing. The micro-contact printing is generally performed at room temperature and employs low contact forces in the order of about 100N. The hot embossing process is performed in an apparatus capable of generating and maintaining elevated temperatures. Further, hot embossing employs high contact forces approximately an order of magnitude larger than the forces used in micro-contact printing. Hot embossing includes at least two basic steps. The first is that the thin polymer film on a substrate is embossed with an embossing die or mold to form the nanostructure in the film. The second step is that ultimately, the embossing mold and film are separated. FIG. 1 is a schematic elevation view of a conventional hot embossing apparatus 1. The apparatus includes a top heater 2, a bottom heater 4, and a stamp or embossing mold 6. The apparatus operates generally as a hot press. The stamp 6 is connected to the bottom heater 4 which heats and maintains the stamp temperature at a desired level. The stamp 6 and bottom heater may be fixed or movable. The top heater 2 is movable in the direction indicated by arrow 7 relative to the stamp 6. The substrate S as seen in FIG. 1 is placed between the stamp 6 and top heater 2. The top heater is moved to press substrate S against the stamp 6 as shown, which effects formation of the nanostructure in the thin film on the substrate. As can be realized from FIG. 1, the step of separating the embossing stamp from the film on the substrate has presented difficulty in conventional hot embossing techniques. For example, in some conventional hot embossing systems a wedge or other prying tool is inserted manually, in a lateral direction between mold and film, in order to effect separation therebetween. As it acquires purchase under the mold, the wedge or prying tool is forced over and against the thin film on the substrate which may result in disruption or damage to the very nanostructure formed by applying the mold. Further, due to the direction in which the wedge or prying tool is applied, control of the forces applied against the substrate is difficult which may result in breakage and total loss of the substrate. In view of the number of IC or MEMS devices that may be formed on a substrate, the cost for loss of a single substrate may be significant. The present invention overcomes the problems of conventional hot embossing systems as will be described in greater detail below.
In accordance with an embodiment of the present invention, a nanoimprinting apparatus for imprinting nanostructure on a workpiece is provided. The apparatus comprises a frame, a platen, an embossing tool, and a separating tool. The platen is connected to the frame for supporting the workpiece. The embossing tool is connected to the frame for imprinting the nanostructure on the workpiece. The separating tool is connected to the frame for separating the workpiece and embossing tool. The separating tool has a workpiece engagement surface for engaging the workpiece when separating the workpiece and embossing tool. The embossing tool extends through the separating tool.
In accordance with a method of the present invention, a method for imprinting nanostructure on a workpiece is provided. The method comprises providing a press having a platen, an embossing tool and a separating tool. The method further comprises providing the separating tool with an opening formed therein, placing the workpiece on the platen, moving the embossing tool through the opening and the separating tool, and separating the workpiece and embossing tool. The embossing tool is moved through the opening in the separating tool to contact the workpiece. The workpiece and embossing tool are separated with the separating tool. The separating tool engages the workpiece and effects separation between the workpiece and embossing tool.